Lipotropin
| pro-opiomelanocortin | |
|---|---|
| Identifiers | |
| Symbol | POMC |
| Entrez | 5443 |
| HUGO | 9201 |
| OMIM | 176830 |
| RefSeq | NM_000939 |
| UniProt | P01189 |
| Other data | |
| Locus | Chr. 2 p23 |
Lipotropin is a hormone produced by the cleavage of pro-opiomelanocortin (POMC). The anterior pituitary gland produces the pro-hormone POMC, which is then cleaved again to form adrenocorticotropin (ACTH) and β-lipotropin (β-LPH).
β-Lipotropin
β-Lipotropin is a 90-amino acid polypeptide that is the carboxy-terminal fragment of POMC. It was initially reported to stimulate melanocytes to produce melanin. It was also reported to perform lipid-mobilizing functions such as lipolysis[1] and steroidogenesis. However, no subsequent studies have been published that support these early findings and no receptor has been identified for β-lipotropin.
β-Lipotropin can be cleaved into smaller peptides. In humans, γ-lipotropin, β-MSH, and β-endorphin, are all possible fragments of β-lipotropin.[2] β-Lipotropin is the predominant opioid of the anterior human and rat pituitary gland. It is found in essentially equimolar concentrations to that of corticotropin. Evidence shows that β-Lipotropin is metabolized into endorphins that can greatly affect mood and behavior and is thus regarded as a prohormone.[3]
γ-Lipotropin
γ-lipotropin is the amino-terminal peptide fragment of β-lipotropin. In humans, it has 56 amino acids. Gamma lipotropin is identical to the first 56 amino acid sequences of β-lipotropin. It can be cleaved to β-melanocyte stimulating hormone.
Use in sport
Lipotropin has also, under its alternate name AOD-9604 (Anti-Obesity Drug-9604),[4] been connected with controversies in Australian Rules Football. Allegations have arisen around the use of the drug and its administration to players of the Essendon Football Club as a supplement, including weekly administration to players in the 2012 season. The matters are currently under investigation due to the relationship between Lipotropin and growth hormones, as noted by club medical staff.[5]
References
- ↑ Choh Hao Li; David Chung (1976), "Isolation and structure of an untriakontapeptide with opiate activity from camel pituitary glands", Proc. Natl. Acad. Sci. USA, 73 (4): 1145–8, PMC 430217
, PMID 1063395 - ↑ Joachim Spiess; Charles D. Mount; Wendell E. Nicholson; David N. Orth (1982), "NH2-Terminal amino acid sequence and peptide mapping of purified human β-lipotropin: Comparison with previously proposed sequences", Proc. Natl. Acad. Sci. USA, 79 (16): 5071–5, Bibcode:1982PNAS...79.5071S, PMC 346829 , PMID 6956916, doi:10.1073/pnas.79.16.5071
- ↑ Lazarus, L H; Ling, Guillemin (June 1, 1976). "beta-Lipotropin as a prohormone for the morphinomimetic peptides endorphins and enkephalins". Proceedings of the National Academy of Sciences of the United States of America. 73 (6): 2156–2159. doi:10.1073/pnas.73.6.2156.
- ↑ Peptides Direct information page, accessed 26 August 2013
- ↑ AFL Statement of Charges against James Hird and Essendon Football Club, accessed 26 August 2013
External links
- beta-Lipotropin at the US National Library of Medicine Medical Subject Headings (MeSH)
- gamma-Lipotropin at the US National Library of Medicine Medical Subject Headings (MeSH)